In using a conventional automatic exposure control type television camera indoors, if for instance, the illuminating light on the ceiling appears directly in the picture or there is a bright window behind a main object to be photographed, the automatic exposure control circuit's operation is adversely affected by these bright objects such that a correct or suitable exposure value cannot be obtained for the main object. This is because the composite video signal for the entire scene is used to perform exposure control. Especially in a television camera intended for home use, the illuminating light is often insufficient and accordingly the signal of the main object is liable to be execessively underexposed. Even in using such a camera outdoors, the same phenomenon can occur, for example, if a main object is in the shadow of a tree with a bright sky as the background in the picture.
In order to eliminate the difficulties due to the above-described phenomena, cameras having a back-light correcting circuit or a manual exposure switching circuit have been proposed in the art. In the back-light correcting circuit, an exposure value is set one or two steps higher than the value at which it would be set without correction by operation of a correcting switch or the like. However, it is not always possible for the back-light correcting circuit to provide a suitable exposure value for an object to be photographed. Theoretically, a correct exposure can be provided for a main object to be photographed by switching from automatic exposure control to manual exposure control. However, this increases the number of steps required for the exposure control making that method rather troublesome.
In view of the foregoing, it is an object of the invention to provide a television camera which can, irrespective of the illumination of an object being photographed, readily provide a suitable exposure value substantially at all times.